Lubrication of print wires



Feb. 7, 1967 v. R. SIMPSON 3,302,557

LUBRICATION OF PRINT WIRES Filed May 29, 1964 2 Sheets-Sheet 1 PRINT &

CARRIAGE CONTROLS ATTORNEY Feb. 7, 1967 v. R. SIMPSON LUBRICATION OF PRINT WIRES 2 Sheets$heet 2 Filed May 29, 1964 United States Patent C) 3,302,557 LUBRICATION OF PRINT WIRES Victor R. Simpson, Owego, N.Y., assignor to International Business Machines Corporation, New York, N.Y., a corporation of New York Filed May 29, 1964, Ser. No. 371,195 6 Claims. (Cl. 1011) This invention relates generally to lubrication and it has reference in particular to an arrangement for forced lubrication of a plurality of print wires such as used in a wire printer or the like.

Generally stated, it is an object of the present invention ot effect improved lubrication of a plurality of print wires which are moved longitudinally back and forth in guide tubes to present different character patterns in a print wire matrix.

More specifically, it is an object of this invention to provide for forcing sufiicient oil into the guide tubes of a wire printer to prevent binding between the wires and wire guide tubes of the printer.

Another object of the invention is to force sufiicient oil into the guide tubes of a wire printer to prevent the entrance of foreign particles into the space between the wires and guide tubes at the print head.

It is also an object of this invention to provide for using longitudinal movement of a drive slug secured to the end of a print wire to pump oil into a guide tube in which the print wire moves back and forth, thereby matching the lubrication of the print wire to its lubricating requirements.

Yet another object of this invention is to provide a drive slug which is secured to one end of a print wire slidably disposed in an elongated guide tube with a bore to receive the end portion of the print wire and guide tube, so that the end of the guide tube can act as a piston for forcing oil into the guide tube under pressure.

It is also an important object of this invention to provide a drive slug secured to one end of a print wire slidably disposed in a guide tube, with an oil sump recess adjacent the end of the guide tube and adjoining a guide tube receiving bore, to insure an adequate supply of oil to the bore during each stroke of the print wire.

Another object of the invention is to provide for selectively lubricating in accordance with the activation thereof a plurality of print wires which are selectively movable back and forth a relatively short distance in flexible guide tubes between print and non-print positions.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of the preferred embodiment of the invention as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a schematic representation in perspective form of a serial printer which embodies the principles of the present invention;

FIG. 2 is a side elevation partially sectioned and to an enlarged scale of the wire support, electrostatic clutch and drive mechanism used for driving the print wire elements of the printer of FIG. 1;

FIG. 3 is a still further enlarged sectional view in part of a type slug, print wire and associated guide tube of the printer of FIGS. 1 and 2 in the non-print position; and

FIG. 4 is a similar enlarged sectional view of a type slug, print wire and associated guide tube of FIG. 3 showing the type slug advanced to the print position.

Referring to the drawings:

The printer apparatus of FIG. 1 comprises a print unit for printing characters one at a time in successive positions along a print line and is generally of the type shown 3,352,557 Patented Feb. 7, 1967 and described in detail in the copending application of Clyde I. Pitch and Fred Saltz entitled Incremental Printer and Printer Plotter, application Serial No. 157,-

187, filed December 5, 1961, now Patent No. 2,326,351, and assigned to the assignee of the present invention. As described therein a print medium 10 such as a continuous forms paper document is moved past the print line by any conventional means including a platen 11 rotatably driven by suitable control means 12 connected to a shaft 13. The mechanism for positioning and advancing the paper may take the form of any one of a number of mechanisms which are well known to the art, having the capability of advancing the paper one or more line spaces at a time in coordination with the printing portion of the cycle of operation. The printing of characters on the paper 10 is as described therein obtained from a printing unit having a plurality of longitudinally movable print wires 14 grouped together at one end to form a matrix print head 15. The wires 14 are guided in flexible guide tubes, the tubes being, for example, grouped in a bundle to provide a flexible configuration 16 between a support 17 and the print head 15.

In accordance with the principles known in the printing art, each of the print wires 14 is selectively individually movable longitudinally within its own guide tube, to form in combination with the other wires, various characters at the matrix print head 15. The selective movement of the different print wires 14 is under the control of means such as, for example, a continuously rotating electro-adhesive rotor 18 driven by means of a motor shaft 19. The wire elements are selectively coupled to the rotor member 18 in a manner to be more fully described hereinafter, by a print head motion and character selector control shown generally at 20 and adapted to receive coded electrical input signals from a computer, a transmission line, a data card, magnetic tape or the like. Character imprints are formed on the print medium 10 when different ones of the individual wires are either driven by the rotor 18 forward from the matrix of print head 15 to strike a ribbon 21 against the paper 10, or are impinged against by the ribbon and paper, in wellknown manners.

As described, the print head 15 is moved incrementally along the print line, and characters formed by the matrix of wires of print head 15 are placed serially at successive positions along the print line. The mech anism for transporting the print head 15 comprises, as shown schematically, a pair of spaced-apart, continuously rotating drive members 23 and 24 which are selectively connectable to a common transport clutch band 25 to which print head 15 is attached in a suitable manner. Drive member 24 is a continuously rotatable electroadhesive rotor rotatable in a clockwise direction for advancing the print head 15. For selectively stopping the forward motion of the print head 15, drive number 23 is an electro-adhesive rotor continuously rotatable in a counterclockwise direction. The clutch band 25 is made of an electrically conductive metal such as steel, so that electric voltages applied to the rotors 23 and 24 cause the band 25 to be electrically attracted thereto.

For the purpose of providing lubrication for the wires 14 in their respective guide tubes, means such as a pump 27 maybe provided, being driven for example by the shaft 19 and connected by means of a conduit 28 to a troughlike member 30 attached to the print wire support 17, to provide a continuous reservoir of oil for lubricating the print wires.

As previously stated, the printing of characters on print medium 10 is effected by selectively driving various combinations of print wires so that the ends thereof strike print ribbon 21 against the paper document 10. The mechanism for driving the print wires may be more clear- 1y understood by reference to FIGURE 2. As shown therein, each of the guide tubes 14a for the wires 14 is secured at the end remote from the print head 15 to a support plate 17b adjacent its lower edge, being for example, soldered or otherwise secured thereto so as to project slightly beyond the lower edge of the plate which forms part of support 17. Each of the print wires 14 at the end remote from the end formed into the matrix of print head 15 is connected to a drive slug 32 which is slidably disposed on a cover plate portion 17a of the support 17, which extends below the edge of and is suitably secured to support plate 17b, being maintained in slidable relation therewith by means of a slug cover plate 170 which is secured by screws (not shown) to the cover plate 17a and a stop member 17d having an end portion positioned in a recess 17:: in the slug 32 to limit its sliding movement. Longitudinal motion of the drive slug 32 is obtained from a print bar 36 which is slidably mounted on supports 38 and 40 and has a lug 42 disposed in a recess 43 adjacent the end of the drive slug 32. A fiat spring 45 attached to a support block 46 bears against a lug 47 on the print bar to bias the print bar 36 to its retracted or non-print position.

For driving each of the print bars 36, electrostatic clutch rotor 18 is rotatably mounted on a shaft 19. The connection of each print bar 36 to the rotor 18, which is continuously rotated by means of motor shaft 19, is effected through an individual clutch band 52 having one end insulatingly connected to the rear end of the print bar 36 with its opposite end anchored to a stationary support 54. The band 52, which is arranged to have a portion of its surface in contact with the periphery of the rotor 18, may be provided with a slack take-up bend 56. It will be understood that a separate clutch band 52 is connected to each of the various print bars so that there is the necessary individual mechanical connection between the rotor and each of the print bars as described, for driving the individual print wires. The electrical arrangement of the clutch band 52 and rotor 18 is such that voltage may be applied to the band 52 selectively through controls 20 so that electro-adhesion is obtained while the voltage is applied, causing the band 52 to be mechanically driven by the rotor 18, to thereby apply a driving force to the bar 36 for moving or advancing the print slug 32 and hence print wire 14 to the print position.

As the print wires 14 are moved back and forth in their guide tubes 14a between the print and non-print positions, not only is appreciable friction encountered between the print wires and the sidewalls of the guide tubes, but in addition, the continued impacting of the print wires at the print head 15 against the carbon ribbon 21 causes particles of carbon from the ribbon to become lodged between the print wires and the side walls of the guide tubes at the print head end, thus causing a binding of the print wires in the guide tubes. To overcome these obstacles, adequate lubrication of the print wires in the guide tubes is essential. In order to provide metered, forced lubrication of the print wires 14 in the guide tubes 14a, oil is supplied from the pump 27, which may comprise a disc 60 secured to the drive shaft 19 of the rotor 18 and arranged to dip into a supply of oil in an oil sump 62 to provide a steady flow of oil from the periphery of the disc through the conduit 28 in a manner well known in the art. This conduit is connected by means of a tubular boss 64 to the trough 30, which is secured to the slug cover plate 17c, and associated with the cover plate 17a for the purpose of providing an oil reservoir adjacent the ends of the guide tubes and the upper ends of the print slugs.

Referring to FIGS. 3 and 4, it will be seen that the print wire 14 enters the print slug 32 through an enlarged axial bore 66 providing an annular space which surrounds the portion of the print wire within the body of the print slug 32. The print Wire is suitably secured within the print slug 32 being, for example, molded therein with, for example, a turned-over or hook portion (not shown) embedded in the body of the slug 32 to secure it therein. As shown, the bore 66 is of sufiicient size to receive with a sliding fit the projecting end portion of the guide tube for the print wire 14 which is shown as surrounded with a sleeve 14b of a plastic material which is shrink fitted thereon to provide a workable diameter for the purpose intended. Immediately adjacent and opening into the bore 66 is a recess 68 in the print slug, which is of less depth than the bore 66 and acts as an oil sump for feeding oil into the bore 66 when the slug is in the non-print position as shown in FIG. 3 with the print wire 14 retracted. It will be noted that in this position the end of the guide tube 14a is within the outer end of the bore 66, but is clear of the bottom of the recess 68, so that oil 69 supplied by the conduit 28 to the trough-like oil reservoir 30 may flow into the recess 68 and thence into the bore 66 surrounding the print wire 14 so as to substantially fill the bore and recess.

When the print wire 14 is activated by the drive slug 32, by reason of its print bar 36 being activated by its clutch band 52, the print slug 32 moves upwardly about the sleeve covered projecting end of the guide tube 14a, which enters axial bore 66, compressing the oil therein and forcing it to flow upwardly into the clearance space between the print wire and the side wall of the guide tube. Each time the print slug 32 is activated, oil 69, which is at all times maintained in the recess 68 and bore 66, by reason of the trough-like reservoir 30 being maintained in the full condition, is entrapped in the axial bore 66 and forced up into the guide tube by a pump action, to effectively lubricate the print wire in the guide tube. This not only prevents binding or galling of the print wire in the guide tube, but in addition it has been found effective in preventing the entry of foreign material into the guide tube at the print head end, and thus prevents binding of the print wire from this cause.

In a typical application, the print wires 14 are of .008 inch diameter rocket wire or high tensile strength steel. The guide tubes 14a are of stainless steel tubing .015 inch outside diameter, .010 inch inside diameter, and the outside diameter of the plastic sleeve 14b is on the order of .028 inch. The coaxial bore in the print slug is preferably .031 inch diameter; the total movement of the print slug 32 is .084 inch; and the compression portion of the stroke or movement of the print slug, after the end of the guide tube 14a is beyond the bottom of recess 68, is on the order of .054 inch, being approximately twice the amount of the clearance of the end of the guide tube 14a above the bottom of the recess 68 in the retracted or non-print position. With IBM #6 lubricant which is about a #10 SAE oil, a clearance on the order of .003 inch between outside diameter of the projecting end of the sleeve about the end of the guide tube and the axial bore in the print slug has been found to give the maximum lubrication. Satisfactory performance has been secured with clearances within a range of .001 to .005 inch. The print slug is made of a thermoplastic acetyl resin having a trade name, Delrin, while the sleeve about the projecting end of the guide tube is of a tetrafluoroethylene polymer known as Teflon. It is expanded, slipped in place and then shrunk on by heating to give a tight fit.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In combination a relatively long flexible print wire,

a flexible guide tube disposed to slidably receive said print wire,

support means for said guide tube adjacent one end thereof for securing said end with a projecting end portion, a

means for moving said wire longitudinally in said tube including a drive slug attached to the wire at said projecting tube end and having an axial bore about a portion of the wire open at the end adjacent the tube and closed at the end remote from the tube, said slug having a recess on one side and opening into the bore at the end adjacent the tube and of less depth than said bore,

means for actuating said slug longitudinally between positions in which the tube end enters the bore be yond the bottom of the recess and in which the tube end clears the portion of the bore beyond the bottom of the recess,

and means supplying oil to said recess for admission to the bore when the tube end clears the portion of the bore beyond the bottom of the recess.

2. In combination,

an elongated flexible guide tube,

a wire positioned in said guide tube longitudinally movable therein and having end portions projecting therefrom,

support means for securing one end of the guide tube with said end projecting therefrom,

end means secured to a projecting end of the wire at the support means end comprising an elongated body having an axial bore about the wire to receive the projecting guide tube end in a sliding fit in one position of the end means, said body having an enlarged recess immediately adjacent said bore and connected with the outer portion of said bore,

means on said support means slidably supporting the end means of the Wire and providing a trough-like cavity adjacent the end of the guide tube,

means for supplying oil to said cavity to fill the recess and axial bore in the end means,

and drive means actuating the end means in a back and forth manner to position the end means about the tube end in one position and withdraw the end means from about the tube in the other positions.

3. In combination an elongated flexible guide tube having an internal diameter on the order of .010 inch and an external diameter on the order of .015 inch inch,

:1 print wire having a diameter on the order of .008 inch slidably positioned in said tube to project from the ends,

support means securing the guide tube with an end portion projecting therefrom,

a sleeve about the projecting portion having an outer diameter on the order of 028 inch,

a drive slug secured to the wire at the projecting tube end having an axial bore of approximately .031 inch diameter disposed to receive the projecting end of the guide tube and having a recess of less depth than the depth of the bore adjacent to and opening into the outer end of said bore,

drive means actuating the drive slug back and forth between positions with the tube end withdrawn from the bore but within said recess, and with the tube end in the bore a distance that is greater than the withdrawal distance therefrom,

and means supplying oil to the recess in the drive slug.

4 In combination a flexible guide tube,

a flexible print wire slidably disposed in said tube, support means securing the guide tube adjacent one end with an end portion projecting therefrom,

a drive slug secured to the end of the wire at the projecting tube end having an axial bore disposed to receive the projecting end portion of the tube,

means disposed in spaced relation to the support means securing the drive slugs in sliding relation to the support means,

means including a conduit furnishing oil between the slug securing means and the support means,

and drive means having a part engaging the drive slug to move it axially between positions in which the tube end is recessed in and is with-drawn from the axial bore.

5. In combination a flexible tubular guide,

a print wire slidably disposed in and projecting beyond the ends of the guide,

support means including means securing the guide adjacent one end with a projecting end beyond the support means,

a guide slug secured to an end of the wire at the projecting tube end and having an axial bore closed at its inner end containing a portion of the wire and disposed to receive the projecting tube end with a sliding fit therein, said guide slug having a recess adjacent and opening into said bore at its open end and having a depth of less than one-third of the depth of the bore,

means including a cover plate and a slug comb disposed in predetermined spaced relation with the support means to slidably align the slug relative to the support means,

means including a conduit sup-plying oil to the space between the cover plate and the slug comb,

and drive means including a member engaging the drive slug for actuating the guide means back and forth to position the tube end within the bore a distance approximately twice the distance between the bottom of the recess and the end of the tube when it is withdrawn from the bore.

6. In combination a plurality of flexible tubular guides,

a flexible print wire slidably disposed in each guide and extending therefrom,

support means securing the guides in predetermined spaced relation adjacent one end with predetermined projecting end portions,

a sleeve secured about each of the projecting end portions,

an elongated drive member secured to each wire having an axial bore about a portion of the wire closed at the inner end but open at the outer end to receive the corresponding tube end with a clearance fit of the order of one-seventh the diameter of the outside of the tube and sleeve,

comb means disposed in spaced relation with the support means slidably locating the drive members relative to the support means,

means supplying oil to the space between the comb means and support means to fill the axial bores,

and drive means operatively connected to the drive member to move it back and forth between a position in which the tube is clear of the bore a distance approximately equal to the outer diameter of the tube and sleeve and a position in which the end of the tube is recessed in the bore substantially twice the outer diameter of the tube and sleeve.

Reterences Cited by the Examiner UNITED STATES PATENTS 2,787,952 4/1957 Roche 101-93 2,909,996 10/1959 Fitch 101-93 2,911,085 11/1959 Leathers 197-1 2,928,338 3/1960 Wockenfuss 101-93 3,236,351 2/1966 Fitch et a1. 197-1 WILLIAM B. PENN, Primary Examiner. 

1. IN COMBINATION A RELATIVELY LONG FLEXIBLE PRINT WIRE, A FLEXIBLE GUIDE TUBE DISPOSED TO SLIDABLY RECEIVE SAID PRINT WIRE, SUPPORT MEANS FOR SAID GUIDE TUBE ADJACENT ONE END THEREOF FOR SECURING SAID END WITH A PROJECTING END PORTION, MEANS FOR MOVING SAID WIRE LONGITUDINALLY IN SAID TUBE INCLUDING A DRIVE SLUG ATTACHED TO THE WIRE AT SAID PROJECTING TUBE END AND HAVING AN AXIAL BORE ABOUT A PORTION OF THE WIRE OPEN AT THE END ADJACENT THE TUBE AND CLOSED AT THE END REMOTE FROM THE TUBE, SAID SLUG HAVING A RECESS ON ONE SIDE AND OPENING INTO THE BORE AT THE END ADJACENT THE TUBE AND OF LESS DEPTH THAN SAID BORE, MEANS FOR ACTUATING SAID SLUG LONGITUDINALLY BETWEEN POSITIONS IN WHICH THE TUBE END ENTERS THE BORE BEYOND THE BOTTOM OF THE RECESS AND IN WHICH THE TUBE END CLEARS THE PORTION OF THE BORE BEYOND THE BOTTOM OF THE RECESS, AND MEANS SUPPLYING OIL TO SAID RECESS FOR ADMISSION TO THE BORE WHEN THE TUBE END CLEARS THE PORTION OF THE BORE BEYOND THE BOTTOM OF THE RECESS. 